Place a skillet over medium-high heat, and add 2 teaspoons cooking oil. When oil is shimmering add chicken breasts. Cook without turning or stirring until browned on the bottom, 2-3 minutes. Flip and continue cooking until the chicken is opaque all the way through, firm to the touch, and browned on the second side, 1-2 minutes more. Remove chicken from the pan, and set aside.